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a m m m 1 6 4 II w lllll T w m d w W Q k Patented June 17, 1919.

3 SHEETS-SHEET 2.

. AL LBRIGHT CONCRETE CONSTRUCTION.

APPLICATION FILED MAR. 9. 1918 i l-"l I'- 1,307ZU3L 3 SHEETS-SHEET 3.

Patented Junem 1919.

E. F. ALLBRIGHT.

CONCRETE CONSTRUCTION.

APPLICATION FILED MAR. 9. 1918A w l l l l l l l l l flammap.

EDWIN F. ALLBRIGHT, 0F ATLANTIC, MASSACHUSETTS, ASSIGNOR TO ADAMSPONJDCOMPANY, INC. OF'BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

CONCRETE CONSTRUCTION.

Specification of Letters Patent.

Patented June 1%, 191%.

To all whom it may concern:

Be it known that I, EDWIN F. ALLBRIGHT, a citizen of the United States,residing at Atlantic, county of Norfolk, and State of Massachusetts,have invented an Improvement in Concrete Constructions, of which thefollowing description, in connection with the accompanying drawings, isa speclfication, like characters on the drawlngs representing likeparts.

The invention hereinafter described relates to concrete construction andmore particularly to slabs having domed or recessed panels.

Heretofore these slabs have been carried by a four-side support in theform of steel beams or concrete beams reinforced by steel. In someinstances the beams are, wholly within and a part of the slab, and inother instances the beams project beneath the slab. This constructionhas been found to be objectionable for various reasons. Among others,the beams add to the amount of concrete and steel required, increase theweight of the slab, increase the bending moments of the slab, and add tothe cost thereof. Also where steel beams are used, they divide the slabinto separate panels with consequent loss of the desirable mutualstrengthening.

effect of panels in a continuous slab.

One of the objects of the present invention is to provide a slab inwhich the necessity for beams extending from column to column iseliminated. As a result, a great saving both in concrete and steel iseffected.

Another object of the invention is to provide solid concrete areas abovethe columns or supports roj ecting a substantial distance therefrom, anddomed or recessed areas be tween said solid areas, the constructionbeing such that the solid areas project toward one another withcantaliver effect and shorten the span of concrete therebetween.

And another object of the invention is to provide dropped panels beneaththe solid concrete areas and above the capitals on the columns, therebydesirably distributing the support from the capitals to the solid areasand contributing to the eflicient cantaliver action thereof insustaining the domed or recessed areas between said solid portions.

With the aforesaid and other objectsin view, the character of theinvention will be best understood by reference to the followingdescription of one good form thereof shown in the accompanying drawings,where1n:

Figure 1 is a perspective view looking toward the under side of aconcrete floor slab embodying the invention supported on columns;

2 is a plan of a portion of the slab;

Fig. 3 is a vertical section through the slab taken on line 33 of Fig.1;

4 on an enlarged scale is a vertical sectlon through two adjacent domesor recesses in the slab showing the forms in place for producing thesame;

Fig. 5 is a perspective view of the type of form used to produce thedomes or recesses in the slab;

Fig. 6 is a perspective view of a portion of the shoring for temporarilysupporting the concrete;

Fig. 7 is a plan showing the arrangement of the shoring for supportingthe dropped panel above one of the columns; and

Figs. 8 and 9 are views of details to be referred to.

Referring to the drawings, the constructlon shown therein as embodyingthe invention comprises columns 1 (Figs. 1 and 2) preferably of concreteand provided with flaring capitals 3 of circular form. The concrete slab5 is mounted on the columns, and in the present instance of theinvention, dropped panels 7 are provided between the capitals and theslab, formed integral therewith and project a substantial distancebeyond the columns and capitals to distribute the support from thecapitals to the slab.

The slab 5 comprises solid concrete panels or areas 9 above and integralwith the dropped panels 7 and bays or areas 11, intermediate said solidareas and dropped panels, having domes or recesses 13 formed in anddistributed throughout the areas 11. Each of these domes or recesses, inthe present instance, is rectangular at its lower end, and the walls orribs between adjacent domes or recesses slope upwardly, therebyproducing a desirable arch effect. The walls or ribs preferably arerelatively thin as compared with the areas of the recesses.

The construction is such that the solid concrete areas and the droppedpanels project a suflicient distance from the columns and toward oneanother to produce a desir throughout through the walls able eantalivereffect and shorten the span of concrete between them without requiringsteel or concrete beams to connect the same. Moreover, the domes orrecesses distributed the concrete areas between the solid areassubstantially diminish the weight of the area of the slab between thesolid areas, and consequently, decrease the burden on the latter.

To further strengthen the construction, suitable reinforcing means maybe provided for the slab, in the present instance, in the form of steelrods or members 17 extending or ribs 15 between the domes or recessesadjacent the lower faces thereo Other reinforcing rods or memhere 19project through the walls between the domes or recesses extendintransversely to the rods 17, the latter, in tlie present instance,passing over and across the rods 19. The rods may have portions 21inclined upward adjacent the juncture of the domed or recessed area ofthe slab with the solid area thereof to strengthen the same againstshearing stresses. Also, the rods may have portions 23 extending throughthe solid areas adjacent the upper surface thereof. The construction andarrangement of the rods is such that they provide tension reinorcementfor the domed or recessed area of the 'slab, and tension reinforcementfor the upper portion of the solid areas of the slab.

To produce the domes or recesses in the slab, a suitable form may beprovided. In the present instance, a form 25 is shown of steel or othersuitable material preferably stringers, washers 3-8 equilateral, andhaving a flange 27 projecting outward from the base thereof. The forms25 may be positioned with the flanges of the adjacent forms engaging oneanother, thereby automatically determining the width of the wallsbetween adjacent domes or recesses. ,7

Suitable shoring may be provided for supporting the forms while theconcrete is being filled in over and around the same to produce theslab, and during a sufficient period to allow the concrete to hardensufliciently. The shoring shown herein comprises posts 29 (Figs. 3 and6) having opposed blocks or brackets 31 detachably secured thereto bybolts 32. These brackets support stringers 33, which also rest onstringers 34 detachably connected by bolts 34: to posts 29 adjacent thecolumns. Thestringers 33 may support transverse stringers 35 separatedby suitable spacing blocks or caps 37 mounted on the upper ends of theposts. The flanges of the forms may rest on the stringers 35, a singlestringer serving to support flanges of two adjacent rows of forms.

To help hold the forms in position on the (Fig. 8) may be placed on thecorners of the flanges 0f the forms and be secured to the stringers bynails 38 projecting through holes in the washers and the spaces betweenadjacent corners, and thence into the stringer In some cases the spanbetween the solid areas of the slab may be such that the standard formsused will not equally divide said span. To provide for such contingency,fillers 27 (Fig. 9) may be provided at the edges of the form flanges 27to increase the width of the ribs or walls between the domes orrecesses. Two stringers may be used to support the flanges of-adjacentforms when lers are used therebetween.

To produce the dropped panel, a sectional form 39 (Figs. 3 and restingon stringers 34 mounted on the osts 29 adjacent the columns. Suitablebrackets 43 may be provided on said posts to contribute to the supportof the forms 39.

The construction of the forms is such that simple shoring requiring aminimum amount of material may be employed to support the forms.

After the concrete has hardened somewhat, the bolts 32 and the blocks 31may be removed from the posts 29 and the bolts 11 may he removed fromthe stringers 41. This will permit removal of all the stringers and thedropped panel forms 39 and leave merely central rows of posts with theircaps supporting the central The other dome forms, removed with thestringers, are then available for use on other construction. The washers38 over the form flanges and nailed to the stringers may assist instarting the forms from the concrete when the stringers are pulled down.As a consequence, a comparatively small number of forms will suffice toproduce the construction, and only a small number need be transportedfrom place to place and stored.

After the concrete has hardened sufliciently, the central posts and capsmay be removed together with the forms above the same, thereby leaving aslab construction having concrete domes or recesses therein as shown inFig. 1.

The bending moments of a slab carried by ams arranged to give afour-side support are materially greater than the bending moments of agirderless or continuous flat slab supported on columns. As aconsequence, slabs having the four-side support must be formed of moreconcrete and be provided with more steel reinforcement than thecontinuous flat slab. Since the slab of the present invention can beconstructed in accordance with the bending moments for a continuousslab, there is a great saving both in concrete and the steelreinforcement required therefor.

Since the concreteon the lower side of the neutral plane, between theportions of the concrete which experience compression and tensionstresses, is weak in tension, it is relarows of dome forms.

tively ineflicient as compared to the concrete above said plane incontributing strength to the slab. By the domes or recesses described,large portions of the concrete beneath said plane are eliminated,thereby reducing the weight of the concrete in the spans between thecantaliver portions of the slab and the amount and weight of steelnecessary to furnish the requisite tension reinforcement therefor.

It will be noted that no beams are required in the spans between thecolumns, but that in place thereof a light slab is employed which issupported by the solid cantaliver areas of the concrete above thecolumns.

It will be understood that the invention is not limited to the specificembodiment shown, but that various deviations may be made therefromwithout departing from the spirit and scope of the appended claim.

What is claimed is 1- In concrete construction, the combination ofcolumns, solid panels resting on said columns and projecting substantialdistances beyond said columns with cantaliver effect, bays between saidsolid panels, each bay having a solid upper surface portion and seriesof transversely extending ribs depending therefrom with deep domes orrecesses be tween said ribs open at the under side of the slab, saiddomes or recesses being distributed throughout the bays to all of themargins of the solid panels, and transversely extending tensionreinforcing members inclosed in said concrete ribs, said solid panelsand bays constituting an integral concrete slab extending continuouslyacross said columns.

In testimony whereof, I have signed my name to this specification.

EDWIN F. ALLBRIGHT.

